Railway signaling



July 26, 1938. J. .LVANHCRN- RAILWAY SIGNALING Original Filed June 15,1935 5 Sheets-Sheet l H P E ME R Y o E TH N N R w o N w 1 s A m a Y m UB H mwwm ww N l S M July 26, 1938. v J..J. VANHORN RAILWAY SIGNALINGOriginal Filed June 15, 1935 5 Sheets-Sheet 2 .wwwmwmmw Q ESQ Eh Q s \amg m ww y R Q & A] \H w INVENTOR James HIS ATTORNEY July 26, 1938. J. J.VANHORN RAILWAY SIGNALING Original Filed June 15, 1935 5 Sheets-Sheet 3N E L m. a NW Aw Bm m S m6 INVENTO'R q-Ja122asJ born H I s ATTORNEY July26, 1938. J. J. VANHORN RAILWAY SIGNALING 5 Sheets-Sheei 4 OriginalFiled June 15, 1935 NTOR July 26, 1938. J. J. VANHORN RAILJWAY SIGNALINGOriginal Filed June 15, 1935 S'Sheets-Sheet 5 All. H

INVENTOR J. Kmlzozn.

James k w m b w M \vqw. .0 ({IL 1 HIS ATTORNEY Patented July 26, 1938PATENT OFFICE RAILWAY SIGNALING James J. Vanhorn, Swissvale, Pa.,assignor to The Union Switch & Signal Company, Swissvale, Pa., a.corporation of Pennsylvania Application June 15, 1935, Serial No. 26,784Renewed October 30, 1936 30 Claims.

My invention relates to railway signaling, and particularly to signalinginvolving wayside signals located along a trackway for governing thepassage of trains.

A feature of my invention is the provision of novel and improvedapparatus for establishing -a distinctive control for each of four tracksections in the rear of an occupied section without the use of linecontrol wires. Each distinctive control is effective to cause acorresponding aspect of the waysidesignals, whereby there is produced afour block, five indication system of signaling. A further feature of myinvention is the provision of apparatus, utilizing a direct current andan alternating current source of power, for controlling wayside signalsin such a manner that trains are kept moving by signal indication in theevent of failure of the alternating current source of power. Otherfeatures and advantages of my invention will appear as the specificationprogresses.

I will describe several forms of apparatus embodying my invention, andwill then point out the novel features thereof in claims.

In the accompanying drawings, Figs. 1A, 1B and 1C are diagrammatic viewswhich, when placed end to end in the order named, illustrate one form ofapparatus embodying my invention. Fig. 2 is a diagrammatic viewillustrating a modification of a portion of the apparatus'shown in Figs.1A, 1B and 10. Figs. 3A, 3B and 3C are diagrammatic views which, whenplaced end to end in the order named, illustrate another form ofapparatus embodying my invention.

Similar reference characters refer to similar parts in each of theseveral views.

Referring first to Figs. 1A, 1B and 10, the reference characters 2 and2A designate the track rails of a stretch of railway track along whichtrafiic normally moves in the direction indicated by the arrows. Theserails are dividedby the usual insulated joints 3 into a plurality oftrack sections V-W, WX, X-Y, YZ, etc.

Each track section is provided with a direct current track circuit whichincludes the track rails in series, a track battery 5 connected acrossthe rails at one end of the section in series with a limiting resistor6, and a polarized direct current track relay R (with a suffixcorresponding to the location) connected across the rails at the otherend of the section. The winding of each track relay R is connecteddirectly with the track rails as will be readily understood by aninspection of Figs. 1A, 1B and 1C. The trackbattery 5 for each sectionis reversibly connected with the track rails by pole-changing contactsof the direct current track relay R for thenext section in advance. Forexample, when the track relay RW is energized the track battery 50f thesection V-W is connected with the track rails 2 and 2A over the frontpoints of the neutral contacts I and I I of the track relay RW to supplycurrent of one polarity, and which polarity I shall refer to in thefollowing description as being of normal polarity. At such time as thetrack relay RW is deenergized, the connection of the battery with thetrack rails is reversed at the back points of contacts l0 and l l tosupply current of the opposite polarity, and which polarity I shallrefer to as being of reverse polarity. The track relay RV for thesection VW, when energized with current of normal polarity, will shiftits polar contacts l2 and 13 into engagement with their respectivelefthand contacts, that is, to the position shown in Fig. 1A. When therelay RV is energized with current of reverse polarity, the polarcontacts I2 and I3 will be shifted to their right-hand positions, thatis, to the positions opposite that shown in Fig. 1A. Each of theremaining track batteries of my system is connected with the rails ofthe associated section in the same manner as battery 5 of section VW,and each of the remaining .direct current track relays responds to thepolarity of the direct current supplied to the associated track sectionin the same manner as the track relay RV.

It will be noted that the relay contacts are not in all instancesdirectly under the relay actuating such contacts. Each such contact,however, is provided with the same reference character as that appliedto the actuating relay.

Each track section is also provided with an alternating current trackcircuit which comprises the track rails in series and which includes asecondary M of a track transformer, designated by the referencecharacter F with a suitable sufiix, connected across the rails'at oneend of the sec- 7 tion and a polarized alternatingcurrent track relay,designated by the reference character A with a suitable sufiix,receiving energy from the rails at the other end of the section. Animpedance 1 for regulating the flow of alternating current in the trackcircuit is connected in series with the secondary l4. The track windingof each relay A is connected, in series with a condenser 8, directlyacross the rails of the associated section. The condenser 8 prevents theflow of direct current in the alternating current relay A, and the highimpedance of the direct current relay R prevents the flow of alternatingcurrent in that relay. The relays R and A, therefore, although connectedto the'same rails, respond only to direct and alternating current,respectively. Each alternating current track relay Ais provided with alocal winding 9 which is connected to a suitable source of alternatingcurrent, the terminals of which are designated by the referencecharacters BX and CX.

Associated with each alternating current track relay is a relay havingaslow release characteristic and designated by the reference character Ewith a distinguishing sumx. The relays E, as will be explained more indetail hereinafter, are provided to prevent certain undesirable flashingand tumbling-down of the signals during the time the polar contacts ofthe alternating current track relays are moving between their normal andreverse positions. I

The primary I5 of the transformerF for each section is connected toterminals BX and CK of the source of alternating current bypole-changing contacts-of the relay-E associated with the section nextin advance, provided that the direct current track relay R for such nextsection in advancevis energized by current of normal p0 larity. Forexample, the primary l5 of the transformer of the section VW is normallyconnected with terminals BX and 0X by a circuit which includes normalpolar contact 2| and front neutral contact l6 ofthe'relay RW, and frontcontacts I! and I8 of the relay EW. That is, when relay RW is energizedin its normal position, alternating current ofnormal polarity issupplied to relay AV when EW i's energized and current .of reversepolarity is supplied to relay AV when relay EW isdeenergized. When relayRW is deenergized or energized in its reverse position the supply ofalternating current for relay AVis disconnected. When relay AV isenergized with current of normal polarity its contacts l9 and Zflwillcome into engagement with their respective left-hand contacts, and whenenergized with current of reverse polarity will come into engagementwith their respective right-hand contacts." When relay AV is energizedso that either its normal polar contact 9 I 9 or'its reverse polarcontact l9l20 becomes closed, the relay EV will be energized and'whenboth such 'co ntacts are opened the relay 'EV will be deenergized,The relay EV, therefore, will become energized or deenergized to closethe front or back points, respectively, of its contacts 22, 23,24 and 25in accordance with the corresponding energization or deenergization ofthe relay AV. H V H 'I he alternating current relays A are of a type inwhich when the track windings of the relays are deenergized, the movablecontacts thereof are moved to their intermediateor open positions, inwhich they do not engage either of the stationary contacts associatedtherewith. V

Each of the remaining transformers F of my system is connected with therails of the .associated section and with the terminalsBX and CX in. amanner similar to transformer FW of the section VW, and each ofv theremaining alternating'current track relays responds to the polarity ofthe alternating current supplied to the associated section in the samemanner as the track relay AV and the relay EV.

. The terminals BX and CX at the various sigfn'al locations throughoutthe track stretch'and from which alternating current is supplied to thelocal windings! of the alternating current relays A, and the terminalsidentified by the same reference characters and from which alternatingcurrent is supplied to the transformers F, and thus to the trackwindings of the relays associated with the adjacent signals in the rear,are supplied with alternating current from a common source so that theinstantaneous polarity of the current supplied to the local and trackwindings of each of the alternating current track relays will beproperly synchronized.

To sum up thus far, each track section is provided with two trackcircuits, a direct current circuit and an alternating current circuitwhich operate independently of each other. The direct current trackcircuit is energized at all times, and is supplied with direct currentof one p0- larity or the other depending upon whether the direct currenttrack relay for the section next in advance is energized or deenergized.The alternating current track circuit is energized only when the directcurrent track relay for the section next in advance is energized withcurrent of normal polarity, and is then supplied with alternatingcurrent of one polarity or the other depending upon whether the slowreleasingrelay repeating the alternating current relay for the sectionnext in advanceis energized or deenergized.

' The track relays R are preferably but not necessarily of theretained-neutral polarized type. v .To govern the passage of trainsthrough the stretch of railway, a wayside signal designated b'y 'thereference character H with an appropriate s'ufiix is located at theentrance of each track section. Each of these signals comprises a topunit T and a lower unit L. These units may take any one of several formsof signal mechanism such: as the semaphore, color light, search light,or position light. 'As here illustrated, each unit isa color lightsignal capable of displaying a green light G,'a yellow light Y and a redlight R.

' The manner in which the lamps of'these signals are controlled willbestbe understood by tracing the circuits and explaining the operationof the apparatus simultaneously. i

A train designated by the reference "character K is shown in the sectionimmediately to the right of location Z. The shunt of the Wheels andaxles of train K will deenergize the track relays RZ and AZ in the usualmanner. RelayRZ being deenergized, current will flow from the terminal'Bof a suitable source of direct current through the back point of contact21 of relay RZ and lamp R of the top unit T of signal HZ to the terminalC of the same source of direct current; so that the lamp R of that unitwill be illuminated. Current will also flow from the terminal B of thedirect current source through the back point of contact 28 of relay 'RZand the lamp R of the lower unit L of signal 'us't p I) The connectionfor the direct current track circuit of the section YZ next in the rearof the section occupied by the train K will be over the back points ofcontacts 30 and SI of the direct current track relay RZ, and hence thetrack relay RY will now be energized with direct current ofreversepolarity to shift its polar contact '36 into engagement with itsright-hand fixed contact 31. Since the alternating current track circuitfor the section Y--Z is open at the front contact 32 of the track relayRZ, the track relay AY will be deenergized as illustrated in Fig. 13'.Consequently, at the location Y, the track relay RY will be energized inthe reverse direction, the track relay AY will be deenergized, and therelay EY will be deenergized.

Therefore, current will flow from the terminal B through front point ofcontact 33 of track relay RY, back point of contact 34 of relay EY andlamp Y of the top unit T of signal HY to terminal C; so that lamp Y ofthat unit will be illuminated. Current will also flow from terminal Bthrough front point of contact 35 of relay RY, polar contact 36-3! ofrelay RY and lamp R of the lower unit L of signal HY to terminal C; sothat lamp R of that unit will be illuminated. The aspect of the signalHY, therefore, will be a yellow light above a red light to indicateprepare to stop at next signal.

Considering next the condition of the track circuits for the sectionX-Y, which is the second section in rear of the section occupied by thetrain, the direct current track circuit for the section X--Y will besupplied with current of normal polarity because the front points ofcontacts 40 and ll of relay RY are closed, and the alternating currenttrack circuit for this section will be deenergized because the normalpolar contact 42-43 of relay RY is opened. Consequently, the relay RXwill be energized with current of normal polarity and the relays AX andEX will both be deenergized.

Current now flows from terminal B of the direct current source atlocation X through front point of contact 44 of track relay RX, backpoint of contact &5. of the relay EX, and lamp Y of the top unit T ofsignal HX to terminal C; so that the lamp Y of that unit will beilluminated. At the same time, current will flow from the terminal Bthrough front point of contact 46 of relay RX, polar contact 41-48 ofrelay RX, back point of contact is of relay EX and lamp Y of the lowerunit of signal HX to terminal C; so that the lamp Y of that unit will beilluminated. The aspect of the signal HX, therefore, will be a yellowlight above a yellow light to indicate proceed at not exceeding mediumspeed. i

I shall next consider the condition of the apparatus for the sectionW-X, the third section to the rear of the section occupied by the trainK. The direct currect track relay RX is energized in the normaldirection so that the connection of the track battery 5 at the locationX is over the front contacts 58 and 5! of the relay RX, and hence thetrack relay RW is energized with current of normal polarity to shift itspolar contacts to the left-hand position. The track relay RX beingenergized in the normal direction and the relay EX being deenergized,thealternating current track circuit forthe section W-X is supplied withalternating current of reverse polarity, so that the track relay AWshifts its polar contacts to the right-hand position. Hence, at locationW, the track relay RW is energized in the normal direction, the trackrelay AW is energized in the reverse direction, and the relay EW isenergized.

Current will therefore flow from the terminal B of the direct currentsource at location W through front point of contact 52 of relay RW,front point of contact 53 of relay EW, and lamp G of the top unit T ofsignal HW to terminal C; so that the lamp G of that unit will beilluminated. Current will also flow from the ter-' minal B of thecurrent source through the front point of contact 54 of relay RW,left-hand polar contact 55-56 of relay RW, front point ofcontact 51 ofrelay EW, right-hand polar contact 58-59 of relay AW, and lamp Y of thelower unit L of signal I-IW to terminal C; so that the lamp Y of thatunit will be illuminated. It follows that the aspect of the signal HWwill be a green light above a yellow light to indicate to a trainapproaching the location approach next signal at not exceeding mediumspeed.

Considering next the condition of the track circuits for the sectionV-W, the fourth section to the rear of the section occupied by the trainK, the track relay RW is energized in the normal direction so that theconnection of the track battery 5 with the track rails of the section VWis over the front points of contacts In and II of the relay RW, and thetrack relay RV is energized with current of normal polarity. The trackrelay AW being energized so that the relay EW is energized, the currentsupplied to the alternating current track circuit for the section V-W isof normal polarity and the track relay AV is energized in its normalposition. Hence, at the location V, both the track relays RV and AV arein their normal positions, and the relay EV is energized.

Current therefore flows from the terminal B through the front point ofcontact 69 of relay RV, front point of contact 23 of relay EV, and

lamp G of the top unit T of signal HV to terminal C; so that lamp G ofthat unit will be illuminated. Current will also flow from batteryterminal B through the front point of contact 6| of relay RV, left-handpolar contact 13-432 of relay RV, front point of contact 22 of relay EV,left-hand contact ZED-453 of relay AV, and lamp G of the lower unit L tobattery terminal C; so that the lamp G of that unit will be illuminated.The aspect of the signal HV, therefore, will be a green light above agreen light to indicate proceed at normal speed.

From the foregoing description, it is evident that a distinctive controlcondition is provided for each of the four successive track sections tothe rear of an occupied section. These control conditions may be summedup as follows: Both track circuits for the section occupied are shuntedin the usual manner to open both the track relays of that section. Thefirst section to the rear of the occupied section has its direct currenttrack circuit supplied with current of reverse polarity and itsalternating current track circuit deenergized. The second section hasits direct current track circuit supplied with current of normalpolarity and its alternating current track circuit deenergized. Thethird sectionhas'its direct currenttrack circuit supplied with currentof normal polarity, and its alternating current track circuit withcurrent of reverse polarity. The fourth section has both its trackcircuits supplied with current of normal polarity. From these differentcontrol conditions, five different signal aspects are obtained, namely,a red light above a red light at the first signal to the rear of a trainto indicate stop, a yellow light above a red light at the second signalto the rear of a train to indicate prepare to stop at the next signal, ayellow light above a yellow light at the third signal to the rear of atrain toindicate proceed at not exceeding medium speed, a green lightabove a yellow light at the fourth signal to indicate approach nextsignal at not exceeding medium speed, and a green light above a greenlight at the fifth signal to the rear ofa train to indicate proceed atnormal speed. I shall term these aspects, stop, approach, medium,approach-medium" and proceed, respectively.

It should be observed that the direct current track relay alone providesthe 'first three aspects of the associated signal, and that thealternating to govern movements of trafiic by a three aspect signalingsystem, providing proach and stop aspects. V

The function of the retained-neutral feature of the direct current trackrelays and the slow to release feature of the E relays will now bepointed out. The signal HY displays a yellow light above a red light toa train in the section XY as long as the train K occupies the section tothe right of location Z. I shall nowassume that while a following trainis approachingthe signal HY, the train K moves on out of the section tothe right of location Z. Under these conditions, the picking up of thedirect current track relay RZ pole changes the direct current trackcircuit for the section Y-Z, and the track relay RY is deenergizedandthen reenergized in its normal direction causing its polar contactsto be shifted from the right-hand position to the left-hand position.The position of the alternating current track relay AY is not changed atthis time, and, consequently, the position of the-relay EY is notchanged. Shifting the polar contact 36 of the medium, ap

track relay RY shifts the signal control circuitfrom that for the lamp Rof the bottom unit L of signal HY to the circuit for the lamp Y of thebottom unit L. The circuit for the lamp Y of the upper unit T is notchanged inasmuch as no change takes place in the position of the relaysAY and EY. 'It follows that the aspect of the signal HY is changed fromthat of a yellow light above a red light to that of a yellow light abovea The retained-neutral feature of yellow light. the track relay RYprevents the back contact 33 of relay RY from becoming momentarilyclosed to give a momentary flash of the lamp R of the top unit T. Thatis, false signal flashing of the signal I-IY is avoided. Furthermore,the retainedneutral feature of relay RY prevents the front contacts 40and 4| from momentarily opening the circuit for the direct current trackrelay RX during the pole changing of the'track circuit for section Y-Z.The energization of the direct current track relays for the remainingsections not being disturbed, successive tumble-down of the signalcircuits for the sections to the rear of location Y is avoided. r

It has been pointed out hereinbefore that the signal HW displays a:green light above a yellow light during the time the train K occupiesthe section illustrated in Fig. 1C. Ishall now assume that while afollowing train is approachingthe signal HW, the train K moves on andvacates the section to the right of location Z. Under theseconditions,the'energization of the alternating current track relay AW ischanged from'reverse to normal. The direct current track relay RX doesnot change its position at this time and hence no change takes place inthe direct current'track relay RW. The shifting of the polar contactjgof relay AW from its right-hand position to its left-hand positiontransfers the signal control circuit from that for the lamp Y of thelower unit of signal HW to that for the lamp G. -The slow releasefeature of the relay EW prevents the back point ofcontact .53 from beingmomene tarily closedto flash the lamp Y of the top unit T; that is,false signal flashing is avoided. Furs thermore, the front points ofcontacts I! and [8 of the'relay EW being retained closed, successivetumble-down of the signal circuits to the rear of location W is avoided.

Referring next to Fig. 2, which illustrates'an alternative method forsupplying direct and alternating current to the track circuits shown inFigs. 1A, 1B and 1C, I have therein shown the secondary M of the tracktransformer FZ connected in multiple with the direct current batteryrather than in series. vided in series with-secondary M to prevent theflow of direct current in the secondary winding and an impedance 65 isprovided in series with the battery 5' to prevent the flow ofalternatingcurrent in the battery 5. Otherwise, the apparatus shown in Fig. 2operates in a manner similar in all respects to' the apparatus embodyingmy invention shown in Figs. 1A,.1Band 1C. Referring now to Figs. 3A, 3Band 30' which illustrate another form of four block, five indicationautomatic signaling system displaying the same indications as thosedescribed for the system shown in Figs. 1A, 1B and 1C, the principaldifference in the apparatus shown in Figs. 3A, 3B and 30 from theapparatus shown in Figs. 1A, 1B and 1C being in the manner in Which thedirect current and alternating current energy. is supplied to the railsof a given section. The form of apparatus illustrated in Figs. 1A, 1Band 1C permits direct current energy and alternating current energy tobesupplied simulta'neously'to the rails of a given section, whereas withthe form of apparatus shown in Figs. 3A, 3B and 30, either alternatingcurrent or direct current, but never both at the same time, is suppliedto the rails of a given section.

Associated with each section is a relay having a slow releasecharacteristic and designated by the reference character D-With adistinguishing suffix. The relay D when energized is effective toprevent direct current energy from being supplied to the direct currenttrack circuits for the section next in rear, and when deenergized iseffective to A condenser 64 is pro-- prevent alternating current energyfrom being Y supplied to the alternating current track circuit for suchnext section in rear. the front point of contact 66 of relay DW of thesection W-X is closed, alternating current energy will be supplied tothe rails of section V-W, and when the back point of contact 66 isclosed direct current energy'vvill be supplied to the rails of sectionV-W. The relay DW is provided with tWo pick-up circuits. one outputterminal of the'rectifier JW through the back point of contact 61 of thedirect current track relay RW, front point of contact 68 of the relayEW, and'relay DW to the other output terminal of the rectifier JW. Theother circuit passes from one output terminal of the rectifier JWthrough the front point of contact 6'! of 'the relay RW, normal polarcontact 69'l0 of the relay RW, back point of contact 68 of relay EW, andrelay DW to the other output terminal of the rectifier JW. The inputterminals of the rectifier JW are directly connected to the terminals BXand CK of the alternating current source of For example, when Onecircuit passes from '18 of relay DZ, the track relay AY will bedeenerenergy. The relay DW, therefore, may be energized when the relayRW is released provided the relay EW is energized, or when the relay RWis energized with current of normal polarity provided the relay EW isdeenergized. Since the relay EW may be energized only when thealternating current track relay AW is energized, the relay DW will beenergized when the track relay AW is energized and the track relay RW isdeenergized, or when the track relay AW is deenergized and the trackrelay RW is energized in its normal position. It is obvious from theforegoing description that either alternating current or direct currentbut not both simultaneously may be supplied to the section V-W.

Each of the remaining track sections of the modification of my inventionillustrated in Figs. 3A, 3B and 3C is provided with a relay W and with arectifier J, each identified by a distinguishing suffix, and eachfunctioning in the same manner as the relay DW and the rectifier JW.

The alternating current relays A employed in the system shown in Figs.3A, 3B and 3C of the drawings are of the type which are employed in thesystem shown in Figs. 1A, 1B and 1C, and have local windings and trackwindings. The 10- cal windings are energized from a source at the signallocation, while the track windings are supplied with current from thetrack rails. The terminals BX and CX at the various signal locationsfrom which alternating current is supplied to the local windings of thealternating current track relays and to the track transformers, andthereby to the track rails and to the track windings of the alternatingcurrent track relays, are all supplied with alternating current from acommon source so that the instantaneous polarity of the current suppliedto the local and track windings of the track relays will be properlysynchronized.

The manner in which the lamps of the signals illustrated in Figs. 3A, 3Band 3C are controlled will best be understood by tracing the circuitsand explaining the operation of the apparatus simultaneously.

The train K is shown in the section immediately to the right of locationZ. The shunt of the wheels and axles of the train K will release thetrack relays R2 and AZ in the usual manner.

Both track relays R2 and AZ being deenergized, current will flow fromthe terminal B of the direct current source of energy through the backpoint of contact H of relay RZ, back point of contact 18 of relay EZ andlamp R of the top unit T of signal HZ to the terminal C; so that thelamp R of that unit Will be illuminated. Current will also flow from theterminal B through the back point of contact 12 of relay RZ, back pointof contact 13 of relay EZ and the lamp R of the lower unit L of signalHZ to the terminal C; so that the lamp R of that unit will beilluminated. The aspect of signal HZ, therefore, will be a red lightabove a red light to indicate stop The connection for the direct currenttrack circuit of the section YZ next in rear of the section occupied bythe train K will be over a circuit including the back points of contacts14 and 15 of the track relay RZ and back point of contact 15 of relay DZso that track relay RY will be energized with direct current of reversepolarity to shift its polar contacts into engagement with its right-handfixed contacts. Since the alternating current track circuit for thesec-- tion YZ is open at the front point of contact gized so that relayEY will also be deenergized. The relay DY will be deenergized becausepolar contact B5-86 of track relay RY is opened.

Current will therefore flow from the terminal B through front point ofcontact 11 of track relay RY, and lamp Y of the top unit T of signal HYto terminal C; so that lamp Y of that unit will be illuminated. Currentwill also flow from terminal B over front point of contact l9 of trackrelay RY, polar contact 8!l8 l of relay RY and lamp R of the bottom.unit L of signal HY to: terminal C; so that lamp R of that unit will beilluminated. Thus, the aspect of signal HY will be a yellow light abovea red light to indicate prepare to stop at next signal.

Considering next the condition of the apparatus for the section. X-Y,which is the second section in the rear of the section occupied by thetrain K, the direct current track circuit for section X-Y will besupplied with current of normal polarity because the front points ofcontacts 82 and 83 of relay RY and the back point of contact 84 of relayDY will all be closed, and the alternating current track circuit forthis section will be deenergized because the front point of contact 84of relay DY is opened. Consequently, the direct current track relay RXwill be energized with current of normal polarity and the relays AX andEX will both be deenergized. Therefore, with the train occupying thesection immediately to the right of signal HZ, the direct current trackrelay RX will be energized by current of normal polarity and alternatingcurrent track relay AX will be deenergized so that relay EX will also bedeenergized. The relay DX will be energized over its control circuitincluding front point of contact 81 of track relay RX, polar contact8889 of relay RX and back point of contact 90 of relay EX.

Current now flows from terminal B at location X through front point ofcontact SI of track relay RX, and lamp Y of the top unit T of signal HXto terminal C; so that the lamp Y of that unit will be illuminated. Atthe same time current will flow from terminal B through front point ofcontact 93 of track relay RX, polar contact 9495 of relay RX and lamp Yof the lower unit L of signal I-IX; so that the lamp Y of that unit willbe illuminated. The aspect of signal HX, therefore, will be a yellowlight above a yellow light to indicate proceed as not exceeding mediumspeed.

I shall next consider the condition of the apparatus for the section WX,the third section to the rear of the section occupied by the train K.The relay DX being energized, the direct current track circuit for thesection W--X will be deenergized so that the direct current track relayRW will be released. The relay EX being deenergized and the relay DXbeing energized, the alternating current track circuit will be suppliedwith current of reverse polarity over the back points of contacts. 96and 9'! of relay EX and the front point of contact 98 of relay DX sothat the alternating current track relay AW will be energized by currentof reverse polarity. Thus the relay EW will be energized because polarcontact 9l00 of alternating current track relay AW will be closed andrelay DW will be energized because its other control circuit includingback point of contact bl of relay RW and front point of contact 68 ofrelay EW will be closed.

Current will therefore flow from terminal B at location W, through backpoint of contact ill! of direct current track relay RW, front point ofcon- 6 tact I 02 of relay uwand the lamp G of the top unit of signal HWto terminal C. Current will also fiow fromtermi'nal B throughback pointof contact 10.3 of track' relay RW, front point of contact I04 of relayEW, reverse polar contact [05 -106 of alternating current trackrelay AWandlamp Y of the lower unit L of signal HW to terminal C. The aspect ofsignal HW, therefore, will be a green light above a yellow light toindicate approach next signal at not exceeding medium speed. Y 7

Considering next the condition of theapparatus for the section V'W, thefourth section in rear of the section occupied by the train K, thedirect current track circuit will be deenergized because the back pointof contact 66 of relay DW is opened, and the alternating current trackcircuit for the section VW will be energized with alternating current ofnormal polarity over the front points of contacts l 01 and lOB ofrelayEW because the front point of contact 66 of relay DW is closed.Therefore, the direct current track relay RV Willbe deenergized and thealternating current track relay AV will be energized by current ofnormal'polarity. The relay EV will be energized because polar contactIMF-H0 of track 7 relay AV is closed and relay DV'will be energized by acircuit including back pointof contact Ill oftrack relay RV and frontpoint of contact I I2 of relay EV. i

Current will therefore flow from terminal B at location V throughbaclipoint of contact H3 of track relay RV, front point of contact I I4of relay EV'and lamp'G of the top unit T of signal HV to terminal'C.Current will also flow from terminal B through back'point of contact H5of track relay RV, front point of contact H6 of relay EV, normal polarcontact Ill- L18 oftrack relay AV and lamp G of the lower unit of signalHV to terminal C. The aspect of signal HV, therefore, will be a green.light'above a green light to indicate fproceedat normal speedf It'willbe noted that when the alternating current track relay is released thedirect current track'relay provides three aspects, namely: me-

dium, approach and"stop, and that when the direct currenttrackrelayisreleasedlthealternating current track relay provides the other twoaspects, namelyr approach-medium and clear. Thus the system embodying myinvention as illustrated in Figs. 3A, 3B and 30 functions in a mannersimilar to the system shown in Figs. 1A, "1B and'lC when the alternatingcurrent is absent. r

Due to the retained neutral characteristics of the direct current trackrelays, and the slow'to release characteristic of the relays 'D and E,it

"will be apparent that the system illustrated in Figs; 3A, 3B and 3C isfree from undesirable signal flashing and tumble-down of signalspreviously pointed out for the system illustrated in Figs. 1A,

' 1B and 1C.

From the foregoing description it is apparent that each of themodifications embodying myinvention provides a four-block, fiveindication signaling system which requires no line control wires,

which is free from undesirable signal flashing.

and tumble-down of signal controlyand which will function to keep tramcmoving ,by signal indications even if the alternating current energy isabsent.

Although I have herein shown and described only 'a few forms ofapparatus embodying my invention, it is understood that various changesand modifications may be made" therein within thescopelo'f theappended'claims' without depart ing from the spirit and scope ofmy'inventi'on.

Having thus described my invention, what I claim is:

1.- A railway signal system comprising a stretch of railway trackdivided into sections, a direct current polarized track relay and analternating current polarized track relay for each section eachreceiving current from the rails of the section, said direct currentrelays 'each effective to prevent the flow of alternating currenttherein and said alternating current relays each con-' nected to therails of'the associated section by controlled jointly by said directcurrent and said alternating current'track relays.

2. A railway trafiic controlling system comprising a stretch of railwaytrack divided into sections, adirect current polarized track relay and.

an alternating current polarized track relay for each section eachreceiving energy from the rails of the section, said direct currentrelays each efiective to prevent the flow of alternating current thereinand said alternating current relays each connected to the rails oftheassociated sec tion by means effective to prevent the flow of directcurrent'therein, means controlled by the track relays of eachsectionforreversibly governing the supply of currents to the rails forthe section next in the rear, and trafiic governing means for eachsectioncontrolled jointly bysaid direct current track relay and said"alternating rails of thesection, a relay controlled jointly by saiddirect current andsaid alternating current track relays of each sectionfor governing the supply of currents to the rails of. the section nextin'the rear, and signaling means for said stretch controlled jointly bysaid direct current and said alternating current relays.

4; A railway signal system comprising a stretch of railway track dividedinto sections, two track relays for each section one direct currenttrack .relay and one alternatingcurrent track relay and each receivingenergy from the rails of the section, said direct current relays eacheffective to prevent the flow of alternating current'therein and saidalternating current relays .each connected to the rails of theassociated section by means effective to prevent the flow of direct cur-;rent therein, two sources of current one direct current and onealternating current, means for supplying the rails of each section withdirect current or with alternating current but not both simultaneously,and signaling means for said sources of current for each section onedirect current and one alternating current, means including a relaygoverned by the direct current track relay and the alternating currenttrack relay of each section for supplying direct current of one polarityor another or alternating current of one polarity or the other but notboth simultaneously to the rails of the section next in rear, andsignaling means for said stretch controlled by said track relays.

6. A railway signal system comprising a plurality of successive sectionsof railway track, two electroresponsive means for each section onedirect current and one alternating current and each selectivelyresponsive to the polarity of the current supplied thereto, said directcurrent electroresponsive means each efiective to prevent the flow ofalternating current therein and said alternating currentelectroresponsive means each effective to prevent the flow of directcurrent therein, two track circuits for each section one direct currentfor controlling the direct current electroresponsive means and the otheralternating current for controlling the alternating currentelectroresponsive means, traflic governing means for each sectioncontrolled jointly by the two electroresponsive means associated withthat section, a source of direct current and a source of alternatingcurrent, and means governed by the electroresponsive means of eachsection for supplying to the track circuits for the section next in therear current from each source of one polarity or of the other polarity.

'7. A railway signal system comprising; a first, a second and a thirdconsecutive track section over which traffic normally progresses in theorder named; a direct current polarized track relay and an alternatingcurrent polarized track relay for each section each receiving currentfrom the rails of the section, said direct current relays each effectiveto prevent the flow of alternating current therein and said alternatingcurrent relays each connected to the rails of the associated section bymeans efiective to prevent the flow of direct current therein, meansgoverned by the direct current track relay for the third section whendeenergized by a train occupying that section to supply direct currentof reverse polarity to the rails of the second section, means governedby the direct current relay for the second section when energized tosupply direct current of normal polarity to the rails of the firstsection, means governed by the direct current track relay of the thirdsection when deenergized to disconnect alternating current from therails of the second section, means governed by the direct current relayof the second section when reversed to disconnect the alternatingcurrent from the rails of the first section, a signal for the thirdsection caused to indicate stop when its direct current relay isdeenergized, a signal for the second section caused to indicate arestrictive indication when its direct current track relay is reversedand its alternating current relay is deenergized, and a signal for thefirst section caused to indicate a less restrictive indication when itsdirect current track relay is normal and its alternating current trackrelay is deenergized'.

8, A railway signal system comprising a stretch of railway track dividedinto sections, two polarized track relays one direct current and onealternating current for each section and each receiving energy from therails of the section, said direct current relays each effective toprevent the fiow of alternating current therein and said alternatingcurrent relays each connected to the rails of the associated section bymeans effective to prevent the flow of direct current therein, meanscontrolled by the direct current track relay for selectively supplyingdirect current of normal or reverse polarity to the rails of the sectionnext in rear, means controlled jointly by both direct and alternatingcurrent track relays for selectively supplying alternating current ofnormal or reverse polarity or no current to the rails of such sectionnext in rear; and a signal for each section controlled by the two trackrelays of that section and arranged to have a first aspect when thedirect current track relay is deenergized, a second aspect when thedirect current track relay is energized reverse and the alternatingcurrent relay is deenergized, a third aspect when the direct currenttrack relay is energized normal and the alternating current track relayis de- 7 energized, a fourth aspect when the direct current relay isenergized normal and the alternating current relay is energized reverseand a fifth aspect when both relays are energized normal.

9. In combination, a stretch of track having a track section, a signalto govern traffic through said stretch and capable of assuming severaldistinctive aspects, a polarized direct current track relay and apolarized alternating current track relay, each receiving energy fromthe rails of said section, operating circuits including neutral andpolar contacts of both said relays-for selectively establishing thedifferent aspects of said signal, a first pole-changer for reversiblysupplying direct current to the rails of the section, a first trafiiccontrolled means responsive to traffic conditions in advance of thesection to govern said first pole-changer, a second pole-changer forreversibly supplying alternating current to the rails of the section,and a second trafiic controlled means responsive to traflic conditionsin advance of the section for governing said second polechanger.

10. A railway signal system comprising a stretch of railway trackdivided into track sections, a polarized direct current track relay andan alternating current polarized track relay for each section eachreceiving energy from the rails of the section, a repeating relay foreach alternating current track relay, contacts operated by each directcurrent track relay to pole-change the direct current supplied to therails of the section next in rear, contacts operated by each repeatingrelay to pole-change the alternating current supplied to the rails ofsuch section next in rear, a signal for each section having severaldifierent aspects controlled by the track and repeating relays of thatsection, and said direct current track and repeating relay eachcharacterized by retaining said pole-changing contacts closed duringperiods of pole-changing whereby signal flashing is avoided.

11. A railway signal system comprising a stretch of railway trackdivided into track sections, a polarized direct current track relay anda polarized alternating current track relay for each section eachreceiving energy from the rails of the section, a repeating relay foreach section governed by the alternating current track relay for thatsection, contacts of each direct current track relay pole-changing thedirect current supplied to the rails of the section next in the rear,contacts of each repeating relay pole-changing the alternating currentsupplied to the rails of the section next in the rear, whereby adistinctive control is effected for each of four consecutive tracksections to the rear of an occupied section, and said direct currenttrack relay as well as said repeating relay being characterized byretaining said pole-changing contacts closed during polechanging periodswhereby successive tumbledown of the track relays to the'rear isavoided.

12. A railway signal system comprising a stretch of railway track, asignal located at the entrance of the stretch to govern traflic enteringthe stretch, said signal capable of displaying a stop indication andfour different proceed indications having varying degrees of speedrestrictions, a direct current relay and an alternating current relay,trafiic controlled means for governing the direct current relay and thealternating current relay, circuit means controlled jointly by saidrelays for selectively governing the indications of said signal andarranged in such a manner that the direct current relay is effective toprovide certainrestrictive proceed indications in the event thealternating current is absent.

13. A railway signal system comprising; a first, a second, a third and afourth track section over which trafiic normally progresses in the ordernamed, two polarized track relays for each section one direct currentand one alternating current and each receiving energy from the rails ofthe section, means controlled by the direct current track relay of thefourth section for discontinuing the supply of alternating current tothe rails of the third and second sections when the fourth section isoccupied, means including a back neutral contact of the direct currenttrack relay for the fourth section for supplying direct current ofreverse polarity to the rails of the third section, means including afront neutral contact of the direct current track relay for the thirdsection for supplying direct current of normal polarity to the rails ofthe second section, means including a normal polar contact of the directcurrent track relay for the second section for supplying alternatingcurrent' of reverse polarity to the'rails of the first section, a signalfor said first section, and means including a reverse polar contact ofthe alternating current track relay for the first section for'causingsaid signal to indicate that the fourth. section is occupied.

14. In combination, a stretch of railway track divided into a pluralityof sections, a source of direct current and a source of alternatingcurrent, means governed by trafiic conditions in said stretch forsupplyingdirect current of normal or reversepolarity to the rails ofeach section and for supplying alternating current of normal or reversepolarity to the rails of each section, a

direct"current polarized track relay connected across the rails of eachsection, and an alternating current polarized'track relay also receivingcurrent from the rails of each section, a con denser connected in serieswith each alternating current track relay, and a signal foreach sectiongoverned jointly by the track relays receiving energy from the rails ofthat section.

15. In combination, a stretch of railway track divided into a pluralityof sections, a source of direct current and a source of alternatingcurrent, means governed by traflic conditions in said stretch forsupplying direct current to the rails of each section or for supplyingalternating current to the rails of each'but not both simultaneously, adirect current track relay and an alternating current track relayconnected across the rails of such section, a condenser connected inseries with each alternating current track relay and a signal for eachsection governed jointly by the track relays associated with suchsection.

16. In combination, a stretch of railway track divided into. a pluralityof sections, a source of direct current for supplying energy'to therails at one end of each section, ,a source of alternating current forsupplying energy to the rails at said one end of each section, saiddirect current and said alternating current being in series, means forgoverning both said direct current source and said alternating currentsource in accordance with traific conditions in said stretch, a directcurrent track relay and an alternating current track relay eachreceiving energy from the rails at the other end of each section, and asignal for each section governed track relays of that section.

17. In combination, a stretch of railway track divided into a pluralityof sections, a source of direct current for supplying energy to therails at one end of each section, a source of alternating current forsupplying energy to the rails at said one end of each section and inmultiple with the direct current source of that section, means forgoverning both said direct current source and jointly by the saidalternating current source in accordance with trailic conditions in saidstretch, a direct currenttrack relay and an alternating current trackrelay each receiving energy from the rails at the other end of eachsection, and asignal for each section governed'jointly by the trackrelays of that section.

18. A railway signal system comprising a stretch of railway trackdivided into sections, two polarized track relays one direct current andone alternating current for each section each receiving energy from therails of the section, said direct current relays each efiective toprevent the fiow of alternating current therein and said alternatingcurrent relays each connected to the rails of the associated section bymeans effective to prevent the flow of direct current therein, meanscontrolled jointly by the direct current track relay and the alternatingtrack relay of each section for supplying either direct current oralternating current each of normal or reverse polarity but not bothsimultaneously to the rails of the section next in rear; and a signalfor each section controlled by the two track relays of that section andarranged to have a first aspect when both track relays are deenergized,a second aspect when the direct current track relay is energizedreverse, a third aspect when the direct current track relay is energizednormal, a fourth aspect when the direct each section controlled jointlyby said two track' relays for that section for governing the supply ofcurrent in such manner that either direct current or alternating currenteach of normal.

or reverse polarity but not both simultaneously is supplied to the railsof the section next in rear; and a signal for each section controlled bythe two track relays of that section and arranged to have a first aspectwhen both track relays are deenergized, a second aspect when the directcurrent track is energized reverse, a third aspect when the directcurrent track relay is energized normal, a fourth aspect when the directcurrent track relay is deenergized and the alternating current trackrelay is energized reverse, and a fifth aspect when the direct currenttrack relay is deenergized and the alternating current track relay isenergized normal.

20. A railway signal system comprising, a stretch of railway trackdivided into track-sections, a signal for each section capable of,displaying a stop indication and four different proceed indicationshaving varying degrees of speed restriction, a direct current trackrelay and an alternating current track relay for each section eachreceiving energy from the rails of the section, means responsive totraffic conditions in advance of each section for supplying directcurrent or alternating current but not both simul taneously to the railsof that action, operating means including neutral and polar contacts ofeach of the relays of a section for selectively establishing thedifferent indications of said signal, said operating means arranged insuch a manner that the direct current track relay is effective tocontrol the stop and certain restrictive proceed indications in theevent of the absence of the alternating current.

21. In combination, a section of railway track, a signal for saidsection capable of displaying a stop indication and three successivelyless restrictive proceed indications, a polarized relay responsive onlyto energy of one character for governing the stop and the two mostrestrictive proceed indications, another relay responsive only to energyof another character for governing the least restrictive proceedindication, a source of energy of one character and a source of energyof said other character, and means effective when the section isunoccupied to reversibly supply energy from the source of said onecharacter to said polarized relay or to supply energy from the source ofsaid other character to said other relay in accordance with trafficconditions in advance of said section, said means being automaticallyeffective to reversibly supply energy of said one character when thesource of energy of said other character is absent.

22. In combination, a section of railway track, a signal for saidsection capable of displaying a stop indication and four successivelyless restrictive proceed indications, a first polarized relay responsiveonly to energy of one character for governing the stop and two mostrestrictive proceed indications, a second polarized relay responsiveonly to energy of another character for governing the two leastrestrictive proceed indications, a source of energy of said onecharacter and a source of energy of said other character, and meansefiective when the section is unoccupied to reversibly supply energyfrom the source of said one character to said first polarized relay orto reversibly supply energy from the source of said other character tosaid second polarized relay in accordance with trafiic conditions inadvance of said section, said means being automatically eifective toreversibly supply energy of said one character when the source of energyof said other character is absent.

23. In combination, a section of railway track, a signal for saidsection capable of displaying a stop indication and three successivelyless restrictive proceed indications, a polarized relay responsive onlyto energy of one character for governing the stop and two mostrestrictive proceed indications, another relay responsive only to energyof another character for governing the least restrictive proceedindication jointly with said polarized relay, a source of energy of saidone character and a source of energy .of said other character, and meanscontrolled by;traiiic conditions in advance of the section effectivewhen said section is unoccupied to reversibly supply energy from onlythe source of said one character to said polarized relay or to supplyenergy from the source of said other character to said other relaysimultaneously with the supply of energy from said one source to saidpolarized relay.

24. In combination, a section of railway track, a signal for saidsection capable of displaying a stop indication and four successivelyless restrictive proceed indications, a first polarized relay responsveonly to energy of one character for governing the stop and two mostrestrictive proceed indications, a second polarized relayresponsive onlyto energy of another character for governing the two least restrictiveproceed indications jointly with said first relay, a source of energy ofsaid one character and a source of energy of said other character, andmeans controlled by traflic conditions in advance of said sectioneffective when the section is unoccupied to reversibly supply energyfrom only the source of said one character to said first polarized relayor to reversibly supply energy from the source of said other characterto said second polarized relay simultaneously with the supply of energyfrom said one source to said first relay.

25. In combination, a section ofrailway track, a signal for said sectioncapable of displaying a stop indication and three successively lessrestrictive proceed indications, 'a polarized track relay responsiveonly to energy of one character connected across the rails at one end ofthe section, another track relay responsive only to energy of anothercharacter also connected across the rails at said one end, saidpolarized track relay controlling the stop and two most restricl tiveproceed indications and said other relay controlling the leastrestrictive proceed indication, a source of energy of said one characterand a source of energy of said other character, and means for reversiblysupplying energy from the source of said one character to the rails atthe other end of said section or for supplying energy from the source ofsaid other character to the rails at said other end in accordance withtrafiic conditions in advance of said section, said means beingautomatically effective to reversibly supply energy of said onecharacter when the energy of said other character is not available.

26. In combination, a section of railway track, a signal for saidsection capable of displaying a stop indication and four successivelyless restrictive proceed indications, a first polarized track relayresponsive only to energy of one character connected across the rails atone end of the sec tion, a second polarized relay responsive only toenergy of another character also connected across the rails at said oneend, said first relay for controlling the stop and two most restrictiveproceed indications and said second relay for controlling the two leastrestrictive proceed indications, a source of energy of said onecharacter and a source of energy of said other character, and means forreversibly supplying the rails at the other end of the section withenergy from said one source or for reversibly supplying therails at saidother end with energy from said gy of said one character when the energyof said other character is not available. 1

27. In combination, a section of railway track, -a signal for saidsection capable of displaying a stop indication and threesuccessively'less restrictive proceed indications, a polarized trackrelay responsive only to energy of one character connected across therails at one end of the section, another track relay responsive only toener- -gy of another character also connected across the rails at saidone end, said polarized relayfor governing the stop and two mostrestrictive proceedindications and said other relay governing the leastrestrictive proceed indication jointly with said polarized; relay, asource of energy of said one character and a source of energy of saidother character, and means controlledby trafiic conditions in advance ofthe section for reversibly supplying energy to the rails at the otherend of the section from only the source of said one character or tosupply energy to the rails at said other end from said other sourcesimultaneously with the supply of energy from said one source.

28. In combination, a section of railway track, a signal for saidsection capable of displaying a stop and four successively lessrestrictive proceed indications, a first polarized track relayresponsive only to energy of one character connected across the rails atone end of said section,

a second polarized track relay responsive only ling' the two leastrestrictive proceed indications of said one character or to reversiblysupply energy to the rails at said other end from the source of saidother character simultaneously with the supply of energy'from said onesource.

29. In combination, a section of railway track, a pair of conductors forsaid section, a first control means responsive only to energy of onecharacter connected across said conductors, a second control meansresponsive only to energy of another character, means connecting saidsecond control means in multiple with said first control means, meansfor supplying said conductors with only energy of said one character orwith energy of said other character simultaneously with energy of saidone character in accordance "with traific conditions in advance of saidsection,

and traiflc governing means for said section governed by said twocontrol means. a r

30. In combination, a section of railway track, a pair'of conductors forsaid section, a direct current'relay connected across said conductors,

an alternating current relay connected in multiple with said directcurrent relay, means for supplying said conductors with only directcurrent or with alternating current simultaneously with direct currentin accordance with traffic conditions in advance of said section, and asignal for said section governed by said two relays. V .1

JAMES J. VANHORN.

